Activated alumina is an extremely porous form of aluminum oxide used as an adsorbent in many different water and gaseous environments, capable of capturing contaminants that would otherwise pollute them.
Water treatment plants utilize electrocoagulation technology to remove fluoride, arsenic and humic acid contaminants from drinking water supplies. Üstelik, natural gas and petrochemical industries utilize electrocoagulation systems to remove moisture, carbon dioxide and trace impurities that could potentially cause corrosion and reduce product quality from gas streams and vapour streams that pass through them.
Removes Fluoride from Water
Activated alumina media can be used as an effective defluoridation method to remove fluoride from water by means of defluoridation, where granules with large surface areas bind with fluoride molecules to defluoridate it for consumption. Üstelik, activated alumina may also serve as a desiccant to absorb moisture from ambient air.
Alumina can also bind with harmful contaminants like arsenic and lead, making it an excellent choice for mining sites where toxic waste may leach into groundwater streams. Utilizing activated alumina helps clean up any hazardous contamination before it has time to spread to other parts of the site or another location.
Before using alumina for defluoridation, an initialisation procedure must first take place. This ensures that any impurities present are reduced below the maximum levels allowed under relevant European directives. Treatment of the alumina with a solution of sodium hydroxide and sulfuric acid has the added advantage of eliminating any humic or fulvic acids formed during storage or usage, and provides further benefits such as eliminating bacteria build-up. Once an alumina filter has been initialised, regular regeneration procedures must be undertaken in order to maintain its contaminant removal capacity. The frequency of regeneration will depend on the level of contamination present in the water source and can be calculated either in terms of gallonage treated or time in service.
Adsorbs Moisture
Activated alumina has a superior moisture adsorption capacity compared to silica gel, making it an excellent solution for applications requiring rapid moisture removal. This is due to activated alumina’s extensive porous structure providing ample surface area for moisture molecules to attach themselves and be bound. However, its optimal moisture uptake occurs at pH levels between 5.5 and 6.5.
Before installing activated alumina into your process equipment, it’s crucial that it undergoes testing. At FEECO’s Innovation Center we perform both thermal and agglomeration testing in-house so we can determine which formulation of activated alumina will provide maximum benefits to meet your application requirements.
As part of the testing process, activated alumina is placed into a nylon bag and saturated with an acid solution to absorb any extra moisture that has collected during activation. Sonraki, it’s heated back up until its original adsorption capacity has been restored, which may take four hours or so. For safety’s sake it should remain stored away from children or pets as well as any chemicals stored nearby.
Alumina can be utilized in your filtration process to remove harmful gases and volatile organic compounds (VOCs) from air, creating healthier indoor spaces. Alumina also serves to effectively eliminate fluorides, arsenic and humic acids in treatment systems or upstream of other filter processes like reverse osmosis or activated carbon filtration processes.
Adsorbs Arsenic
Arsenic is a toxic heavy metal and should be removed from water using various treatment methods such as coagulation and precipitation, membrane filtration and ion exchange. An excellent adsorbent to use when eliminating arsenic is activated alumina made from byproducts of aluminium production which has been heated with caustic soda in order to create expanded crystal lattices, absorbance of water molecules and development of porous structures with high surface areas.
Alumina’s ability to adsorb arsenic is pH dependent, with maximum removal capacity achieved at pH level 5.5. At this level, arsenic can be adsorbed at low concentrations while competing effectively with other ions that activated alumina is capable of adsorbing such as fluoride, selenium and hardness ions.
At various initial concentrations and contact times for Arsenic (III) adsorption on iron acetate-coated activated alumina for arsenic (As(III), performance evaluation showed that its performance can be accurately described using Langmuir and Freundlich isotherm models.
Domestic applications typically use activated alumina to remove arsenic from water using a batch sorption process, typically producing enough treated water per minute for one gallon per minute of household water pressure; two devices can also be connected in parallel if additional capacity is necessary.
Adsorbs Lead
Activated alumina is a highly effective adsorbent for heavy metals such as lead, arsenic and selenium found in water sources, helping remove them and making drinking safe again. Üstelik, activated alumina acts as an excellent desiccant, making use of its properties exploited in pharmaceutical and petrochemical industries for compressed air drying systems or dehydration processes.
Porosity and large internal surface area make alumina an excellent material for absorbing gases, liquids, and dissolved substances. Alumina comes in powder form as well as beads, pellets or granules of various particle sizes to meet various applications; particle sizes impact its bulk density which in turn affects its adsorption capacity; its high surface area results from its activated structure which creates networks of pores and voids within its spheres resulting in high surface area adsorption capacity.
To create this highly adsorptive media, bauxite must first be thermally treated through calcination in a rotary kiln in order to dehydrate it and produce alumina, or aluminum oxide (Al2O3). After this step is completed, another process known as activation involves exposing it to steam at elevated temperatures which eventually creates an extensive network of pores and voids within its original alumina spheres; composition depends on composition of bauxite used as well as temperature and residence time during calcination and activation stages respectively.